#include    <stdio.h>

void swap(int a, int b)
{
    int tmp;
    tmp=a;
    a=b;
    b=tmp;
}

int main(int argc, char *argv[])
{
    int a=10;
    int b=20;
    printf("a=%d, b=%d\n", a, b);
    swap(a, b);
    printf("a=%d, b=%d\n", a, b);
    return 0;
}



